Case Of Prosthetic Joint Infection Research Articles

Successful prophylactic measures for the eradication of Staphylococcus aureus infections in elective hip primary and revision arthroplasty

IntroductionStaphylococcus aureus stands as the predominant etiological agent in postoperative acute prosthetic joint infections (PJI), contributing to 35–50% of reported cases. This study aimed to evaluate the efficacy of dual prophylaxis incorporating cefuroxime and teicoplanin, in combination with nasal decolonization utilizing 70% alcohol, and oral and body lavage with chlorhexidine. Material and methodsWe conducted a retrospective review of electronic health records regarding primary and revision arthroplasties conducted at our institution from 2020 to 2021. Relevant variables linked to prosthetic joint infections (PJI) were documented until the latest follow-up. ResultsA total of 539 operations (447 primary arthroplasties and 92 revision arthroplasties) were performed on 519 patients. There were 11 cases of postoperative acute PJI, resulting in infection rates of 1.6% for primary arthroplasties and 4.3% for revision surgeries. Infections were more prevalent in male patients, individuals with an ASA classification>II, and those undergoing longer operations (>90min). S. aureus was not isolated in any of the cases. ConclusionThe prophylactic measures implemented in our institution have exhibited a high efficacy in preventing postoperative acute PJI caused by S. aureus.

Prosthetic joint infection caused by Mediterraneibacter gnavus following total knee arthroplasty, challenges in anaerobic bacteria identification

BackgroundMediterraneibacter gnavus is a Gram positive, non-sporulated, obligate anaerobe diplococci. It was first described in 1974 by Moore et al. (under the name Ruminococcus gnavus) from faeces and contents of the gastrointestinal tract of humans. It is a relatively common member of the human gut microbiota, nevertheless its role as a pathogenic bacterium has not been completely elucidated yet and it seems to depend on numerous factors, including those of the host. Here we present a case of prosthetic joint infection following total knee arthroplasty by M. gnavus.Case presentationA 74 years old patient was admitted to the emergency department presenting with acute onset of left knee pain and swelling 20 days after total left knee arthroplasty. Follow-up revealed erythema and oedema without signs of fluctuation or purulent discharge from the surgical wound and elevated inflammatory reactants. Synovial fluid was taken for bacterial culture and antibiotic treatment with ceftazidime and daptomycin was established. Examination of the synovial fluid revealed abundant polymorphonuclear leucocytes, without visualizing bacteria. After four days of incubation, anaerobic culture exhibit growth of small, grey, umbilicated colonies in pure culture on Schaedler agar. The microorganism was identified as R. gnavus by MALDI-TOF (Bruker Daltonics) and M. gnavus by 16S ribosomal bacterial sequencing. The isolated showed susceptibility to the most commonly used anaerobicidal antibiotics except for clindamycin. Surgical treatment and infection source control included DAIR (debridement, antibiotics, and implant retention) and vacuum assisted therapy. The patient was discharged after six weeks with a 3-month course of oral amoxicillin as consolidation therapy. Subsequent follow-up revealed adequate wound healing with no signs of infection.ConclusionsMediterraneibacter gnavus have been reported as the causal microorganism in a range of human infections, nevertheless its identification remains challenging. Infection of prosthetic joints by anaerobic microorganisms is uncommon and is not considered in its empirical antibiotic treatment, thus, correct and swift identification of anaerobic bacteria in these cases is paramount.

16S rRNA sequencing reveals microbiota differences in orthopedic implants between aseptic loosening and prosthetic joint infection cases.

Prosthetic joint infection (PJI) and aseptic loosening (AL) are common complications of total joint arthroplasty. An accumulation of evidence indicates the presence of microbial communities on prosthetic implants, but the overall microbial profile is unclear. In this study, we aimed to investigate the differences in the microbial composition of prosthetic implants obtained from PJI and AL patients using the 16S rRNA sequencing method. Patients who underwent revision hip, knee, or shoulder arthroplasty caused by PJI (n = 20) or AL (n = 10) were enrolled in the study. 16S rRNA sequencing targeting the V3-V4 region was performed on the microbial specimens collected from synovial fluid, periprosthetic deep-tissue, and biofilm during the revision surgery. The sequenced raw data were analysed for microbial composition and ecological and differential abundance analyses using bioinformatics tools. The AL group had relatively balanced and higher diversity, with Staphylococcus, Streptococcus, and Veillonella being prominent. In the PJI group, Staphylococcus and Pseudomonas were predominant, especially in deep-tissue samples and biofilm samples, respectively. The differential abundance analysis identified 15 and 2 distinctive taxa in the AL and PJI groups, respectively. Our findings provided preliminary insights supporting the existence of periprosthetic microbiota in orthopedic implants and explaining the differences in microbial composition between the AL and PJI groups.

Complications and Learning Curve Associated with an Imageless Burr-Based (CORI) Robotic-Assisted Total Knee Arthroplasty System: Results from First 500 Cases.

The use of robotic-assisted total knee arthroplasty (RA-TKA) is gaining traction. There is evidence to suggest that RA-TKA can help to optimize the precision and accuracy of implant positioning and that there may be protective effects on surrounding bony and soft tissues. Yet, there are important differences between the various RA-TKA systems currently on the market. One such newly introduced RA-TKA system uses imageless technology and performs bony cuts with the use of a burr-based device. The learning curve and complications unique to this system have yet to be assessed. We evaluated 500 consecutive RA-TKA cases using a newly developed burr-based and imageless system which were done by a single surgeon between the months of October 2021 and February 2023. Operative times were recorded and compared to the previous 150 conventional TKA cases allowing for the learning curve to be calculated using the CUSUM method. Intraoperative and postoperative complications were categorically profiled. The learning curve of this RA-TKA system was found to be 6 cases. Intraoperative complications included unintended bony over resection (n = 3), soft tissue injury (n = 2), and robotic system hardware (n = 2) or software (n = 2) malfunction. Postoperative complications consisted of superficial pin site infection (n = 1) and periprosthetic fracture near the pin sites (n = 1). There were no identified cases of prosthetic joint infection, instability events, or wound complications. The learning curve and the complication profile of a newly introduced imageless and burr-based RA-TKA system were described. This information serves to guide surgeons in adopting this technology and can counsel them regarding the potential pitfalls and challenges associated with its integration into practice. The work sheds light on the complexity and learning curve of the recently released imageless burr-based RA-TKA system. This important information is intended to help surgeons accept this cutting-edge technology by providing advice on any errors and difficulties that can occur when integrating it into clinical practice. This information can help surgeons navigate the complexities of integrating this new burr-based robotic technology into knee replacement procedures, enabling them to make well-informed decisions and receive guidance.

Impact of antibiotic prophylaxis in second-stage surgery in joint prosthesis infection treated with two-stage exchange. A multicenter case-control study.

After two-stage exchange due to prosthetic joint infection (PJI), the new prosthesis carries a high risk of reinfection (RePJI). There isn`t solid evidence regarding the antibiotic prophylaxis in 2nd-stage surgery. The objective of this study is to describe what antibiotic prophylaxis is used in this surgery and evaluate its impact on the risk of developing RePJI. Retrospective multicenter case-control study in Spanish hospitals. The study included cases of PJI treated with two-stage exchange and subsequently developed a new infection. For each case, two controls were included, matched by prosthesis location, center, and year of surgery. The prophylaxis regimens were grouped based on their antibacterial spectrum, and we calculated the association between the type of regimen and the development of RePJI using conditional logistic regression, adjusted for possible confounding factors. We included 90 cases from 12 centers, which were compared with 172 controls. The most frequent causative microorganism was Staphylococcus epidermidis with 34 cases (37.8%). Staphylococci were responsible for 50 cases (55.6%), 32 of them (64%) methicillin-resistant. Gram-negative bacilli were involved in 30 cases (33.3%), the most common Pseudomonas aeruginosa. In total, 83 different antibiotic prophylaxis regimens were used in 2nd-stage surgery, the most frequent a single preoperative dose of cefazolin (48 occasions; 18.3%); however, it was most common a combination of a glycopeptide and a beta-lactam with activity against Pseudomonas spp (99 cases, 25.2%). In the adjusted analysis, regimens that included antibiotics with activity against methicillin-resistant staphylococci AND Pseudomonas spp were associated with a significantly lower risk of RePJI (adjusted OR = 0.24; 95% IC: 0.09-0.65). The lack of standardization in 2nd-satge surgery prophylaxis explains the wide diversity of regimens used in this procedure. The results suggest that antibiotic prophylaxis in this surgery should include an antibiotic with activity against methicillin-resistant staphylococci and Pseudomonas.

Prosthetic Joint Infections Caused by Mycobacterium tuberculosis Complex-An ESGIAI-ESGMYC Multicenter, Retrospective Study and Literature Review.

While tuberculosis remains a significant global health concern, prosthetic joint infections (PJIs) caused by members of the Mycobacterium tuberculosis complex are exceptionally rare. Our objective is to perform a retrospective search of new cases of this disease and analyze all cases available in the literature of tuberculous PJIs, aiming to detect factors that may influence patient outcomes. The ESGIAI and ESGMYC study groups were used to collect information on non-published cases of tuberculous prosthetic joint infections (PJIs). Additionally, a literature review of all published cases of tuberculous PJIs was conducted. All identified cases in the retrospective study and in the literature review were merged and included in the statistical analysis, involving both univariate and multivariate analyses. Fifteen previously unreported cases of tuberculous prosthetic joint infections (PJIs) from four countries were detailed. Among them, ten patients were female, with a median age of 76 years. The hip was affected in 13 cases. Seven patients experienced co-infection with another microorganism. Treatment approaches varied, with 13 patients undergoing implant removal, one treated with DAIR (debridement, antibiotics, and implant retention), and one case was treated with an unknown treatment method. All patients received antibiotic therapy and achieved a cure. The literature review that was conducted detected 155 published cases. Univariate analysis revealed a statistical significance for previous tuberculosis, joint, and no importance of surgery for cure. Tuberculous prosthetic joint infection (PJI) is a rare condition, typically presenting as a localized chronic infection. Antibiotic treatment is essential for the management of these patients, but neither surgical treatment nor duration of treatment seems to have importance in the outcome.

Cutibacterium avidum: A Potent and Underestimated Pathogen in Prosthetic Hip Joint Infections.

Cutibacterium avidum has recently been reported as a rare cause of prosthetic joint infections (PJIs), contrary to Cutibacterium acnes, which is well established as a cause of PJIs, especially in shoulder arthroplasties. Two specific risk factors for PJI due to C. avidum have been reported: obesity and the skin incision approach. Here, we report four cases of hip PJIs caused by C. avidum admitted over a 30-month period at a single center. Whole-genome sequencing revealed that the four C. avidum strains were all individual strains and did not originate from a common source, such as an outbreak. Antibiotic susceptibility tests showed that the isolates were fully susceptible, and none carried known antibiotic resistance genes. In conclusion, the occurrence of four cases of PJI caused by C. avidum over a limited time at a single center may indicate that this pathogen is underestimated and is either emerging or more common than previously recognized. The patients presented overt signs of infection during surgery, indicating that C. avidum is a virulent pathogen. None of the previously reported risk factors for C. avidum PJI applied to these patients as only one was obese and none were operated on using a direct anterior skin incision approach.

1300. Comparison of the Clinical Characteristics and Outcomes of Anaerobic Prosthetic Joint Infections (PJI) and Aerobic PJIs : A Retrospective Review

Abstract Background PJI is an uncommon but serious complication of joint arthroplasties that can result in significant morbidity and cost. There is a paucity of studies in the literature on PJIs caused by anaerobic organisms either as the sole pathogen or part of a polymicrobial infection. The purpose of this study was to compare the clinical presentation and outcomes of PJI caused by anaerobes as opposed to aerobes. Methods This was a retrospective review of 306 patients who met Musculoskeletal Infection Society (MSIS) criteria for PJI from 2014 to 2020 at the University of Iowa Hospitals and Clinics (UIHC). 38 patients with anaerobic PJI were compared to 268 patients with aerobic PJI. Statistical analyses were performed using Pearson’s Chi square, Fisher exact test, t-test, and binary logistic regression. Results PJI with anaerobes represented 12.4% of all PJI cases in our institution, which is higher than the 3-6% reported in literature. Patients with anaerobic PJI had longer duration of symptoms (19.4 weeks vs 10.9 weeks, p = 0.012), were more likely to have a sinus tract on exam (23.7% vs 5.9%, p < 0.001), less fever on presentation ( 13.2% vs 30.2%, p = 0.029), more radiographic abnormalities (50.0% vs 31.1%, p< 0.001), lower erythrocyte sedimentation rate (49.0mm/hr vs 67.7 mm/hr, p = 0.003), lower C-reactive protein (6.6 mg/dL vs 12.1mg/dL, p = 0.004), and more likely to be polymicrobial (42.1%vs 8.0%, p < 0.001) compared to aerobic PJI. There was a higher proportion of anaerobes in shoulder PJIs compared to other joints (39.5% vs 5.5%, p< 0.001). Two-stage exchange was the most common surgical treatment in patients with anaerobic PJI (39.4%) whereas debridement and implant retention was the most common (44.5%) surgical treatment done in patients with aerobic PJI. No significant differences were seen between the two groups in terms of recurrences. Independent factors associated with anaerobic infection were shoulder prosthetic joint (AOR 10.5, CI 3.4 - 32.8) and presence of sinus tract (AOR 10.1, CI 3.1 - 32.6). Conclusion Anaerobic cultures should be performed in patients with PJI, and they should especially be considered on the differential in patients with shoulder PJI, longstanding symptoms, sinus tract on examination and abnormalities noted on radiographs. Disclosures All Authors: No reported disclosures

Acute Prosthetic Joint Infections with Poor Outcome Caused by Staphylococcus Aureus Strains Producing the Panton-Valentine Leukocidin.

The aim of this study was to investigate whether the presence of Staphylococcus aureus (SA) producing the Panton-Valentine leukocidin (PVL) affects the outcome of Prosthetic Joint Infection (PJI). Patients with acute and chronic PJI sustained by SA were prospectively enrolled at the orthopedic unit of "Casa di Cura Santa Maria Maddalena", from January 2019 to October 2021. PJI diagnosis was reached according to the diagnostic criteria of the International Consensus Meeting on PJI of Philadelphia. Synovial fluid obtained via joint aspirations was collected in order to isolate SA. The detection of PVL was performed via real-time quantitative PCR (RT-qPCR). The outcome assessment was performed using the criteria of the Delphi-based International Multidisciplinary Consensus. Twelve cases of PJI caused by SA were included. Nine (75%) cases were acute PJI treated using debridement, antibiotic and implant retention (DAIR); the remaining three (25%) were chronic PJI treated using two-stage (n = 2) and one-stage revision (n = 1), respectively. The SA strains that tested positive for PVL genes were 5/12 (41.6%,). Treatment failure was documented in three cases of acute PJI treated using DAIR, all supported by SA-PVL strains (p < 0.045). The remaining two cases were chronic PJI treated with a revision arthroplasty (one and two stage, respectively), with a 100% eradication rate in a medium follow-up of 24 months. Although a small case series, our study showed a 100% failure rate in acute PJI, probably caused by SA PVL-producing strains treated conservatively (p < 0.04). In this setting, toxin research should guide radical surgical treatment and targeted antibiotic therapy.

Is Corynebacterium striatum an emerging prosthetic joint infection pathogen and how should it be treated?

The aim of this study was to assess the incidence of Corynebacterium striatum prosthetic joint infections (PJI) to determine if an increase has occurred recently. Moreover, susceptibility testing was conducted on C. striatum preserved isolates to determine antibiotic options for these infections. Retrospective review of PJI cases was conducted from 1/2017 through 1/2021 compared to 1/2021 through 7/2022 to determine how many cases of C. striatum have occurred for each of these time points. From these cases, demographics, outcomes and risk factors for C. striatum PJI were recorded. The preserved clinical isolates from these cases were tested for susceptibility to different antibiotics. A statistically significant increase in the proportion of C. striatum PJI cases (1.98 to 7.84, p=0.0489) has occurred over the past 16 months at a single institution. Chronic wounds and exposure to daptomycin were associated with the majority of these cases. Susceptibility testing of the clinical isolates showed uniform susceptibility to vancomycin, linezolid and dalbavancin. Uniform resistance was seen with ciprofloxacin, tetracycline and doxycycline as well. Interestingly, 85.7% of the isolates displayed inducible daptomycin resistance after overnight exposure to daptomycin. C. striatum is an emerging PJI pathogen. It is important for clinicians to be cognizant that this pathogen can have inducible high level daptomycin resistance and that daptomycin is likely not a reliable antibiotic for these infections. While vancomycin and linezolid are the traditional antibiotics to use in these infections, other antibiotics such as dalbavancin, may also have utility, but more research is needed to determine the effectiveness of this antibiotic in C. striatum infections.

Failed 2-Stage Revision Knee Arthroplasty for Periprosthetic Joint Infection—Patient Characteristics and Outcomes

BackgroundChronic prosthetic joint infection (PJI) is most frequently treated with 2-stage revision in conjunction with antibiotic treatment. The aims of this study were 1) to investigate the characteristics of patients who have recurrent infection following 2-stage revision for PJI and 2) to identify risk factors associated with treatment failure. MethodsA multicenter retrospective review of 90 total knee arthroplasty (TKA) patients who underwent 2-stage revision for treatment of PJI from March 1, 2003 to July 31, 2019, and had recurrent PJI was conducted. The minimum follow-up was 12 months (median follow up of 2.4 years). Microorganisms, subsequent revision, PJI control status, and final joint status were collected. The infection-free survival after initial 2-stage revision was plotted utilizing the Kaplan–Meier method. ResultsMean survival time to reinfection was 21.3 months (range, 0.3 to 160.5). There were 14 recurrent infections that were acute PJIs treated with debridement, antibiotics, and implant retention (DAIR), while 76 were chronic and treated with repeat 2-stage revision. The most common pathogen identified for both index and recurrent PJI was coagulase-negative Staphylococci. Pathogen persistence was observed in 14 (22.2%) of recurrent PJIs. In total, 61 (67.8%) patients possessed a prosthetic reimplantation at their most recent follow-up, and 29 (35.6%) patients required intervention following repeat 2-stage. ConclusionOverall, 31.1% of the patients obtained infection control after treatment of a failed 2-stage revision due to PJI. The high rate of pathogen persistence and the relatively low survival time to recurrence suggests a need to more closely monitor PJIs cases within 2 years.

Corynebacterium striatum Prosthetic Joint Infection Successfully Treated with Long-Term Dalbavancin

Arthroplasty surgery is a common procedure that significantly improves quality of life. The most feared complication is prosthetic joint infection (PJI), which occurs more often following revision surgery. Staphylococci are the most prevalent bacteria in PJIs, although many other pathogens have been reported. We describe a case of PJI in a 75-year-old farmer following revision surgery caused by Corynebacterium striatum, an unusual agent which normally occurs in the normal human skin microbiota with perceived low pathogenicity. Following a cemented right-sided total hip arthroplasty in 2006, a one-stage revision due to an osteolytic process in the right femur took place in 2020 with negative intraoperative tissue cultures. Three weeks later, the patient presented a fulminant infection which was treated with debridement, antibiotics, and implant retention (DAIR). Tissue biopsies showed C. striatum in 6/6 samples including small colony variants. Genome sequencing showed that all isolates differed by ≤6 SNPs with the same gene content related to resistance (tet(W) and erm(X)). The patient was sequentially treated with vancomycin, linezolid, and daptomycin, but due to side effects, treatment was changed to 12 weeks of dalbavancin as a 1000 mg loading dose followed by 500 mg intravenously/week. Impaired renal function during vancomycin treatment was normalized, and >1 year after finishing antibiotic treatment the outcome was still favourable. In conclusion, a case of a fulminant early post-interventional PJI due to C. striatum was successfully treated with DAIR and long-term dalbavancin therapy without any adverse reactions.

Clinical and Histological Features of Prosthetic Joint Infections May Differ in Patients With Inflammatory Arthritis and Osteoarthritis.

Background: Patients with inflammatory arthritis are at increased risk of prosthetic joint infections (PJIs), but diagnosis in these patients can be challenging because active inflammatory arthritis produces elevated inflammatory markers that may mimic those seen in PJI. Purpose: In this pilot study, we sought to identify the clinical, microbiologic, and histopathologic features of culture-positive and culture-negative PJI in patients with inflammatory arthritis who underwent total hip arthroplasty (THA) or total knee arthroplasty (TKA). We also sought to obtain preliminary data to support a definitive study of optimal methods for PJI diagnosis in patients with inflammatory arthritis. Methods: We performed a retrospective analysis of TKA and THA patients treated for PJI from 2009 to 2018 at a single tertiary care orthopedic institution. Data were extracted from a longitudinally maintained hospital infection database. We reviewed hematoxylin and eosin slides of osteoarthritis and inflammatory arthritis PJI cases matched 3:1, respectively, by age, sex, and culture status. Clinical characteristics were evaluated using the Fisher exact test, χ2 test, Student t test, and Mann-Whitney U test where appropriate. Results: A total of 807 PJI cases were identified (36 inflammatory arthritis and 771 osteoarthritis cases). Patients with inflammatory arthritis presented younger, had a higher Charlson Comorbidity Index, more frequently used glucocorticoids, were more likely women, and had a higher proportion of culture-negative PJI compared with osteoarthritis patients. Of the 88 inflammatory arthritis cases reviewed for histopathology, a higher proportion of culture-positive than culture-negative PJI cases had >10 polymorphonuclear leucocytes per high-power field and met Musculoskeletal Infection Society criteria but presented with less chronic inflammation. Conclusions: This retrospective prognostic study suggests that culture-negative PJI may be more frequent in patients with inflammatory arthritis than in those with osteoarthritis. Chronic infections, antibiotic use, or misdiagnosis may be contributing factors to unclear PJI diagnoses among culture-negative cases. This preliminary work supports the need for further studies to assess the differences in clinical features between culture-negative and culture-positive PJI in patients with inflammatory arthritis and the ability of biological diagnostic markers to discriminate between them in this population.

AUSTRALIAN CAPITAL TERRITORY PROSTHETIC JOINT INFECTION DATABASE: ANALYSIS OF THE FIRST 100 PATIENTS

Prosthetic joint infections (PJI) are one of the most devastating complications of joint replacement surgery. They are associated with significant patient morbidity and carry a significant economic cost to treat. The management of PJI varies from antibiotic suppression, debridement, antibiotics, and implant retention (DAIR) procedures through to single/multiple stage revision procedures. Concerns have been raised recently in relation to the rising number of revision arthroplasty procedures that are being undertaken in relation to infection. This database aims to collect data on all PJIs that have been managed in the Australian Capital Territory (ACT) region. This will allow us to investigate the microbial trends, outcomes of surgical intervention and patient outcomes within our local population.This database will incorporate diagnostic, demographic, microbiological and treatment information in relation to local PJI cases. The data will be collated from the local infectious diseases database, hospital medical records, and where available the Australian Orthopaedic Association National Joint Replacement Registry Data.The first 100 cases of PJI were assessed. 76% were defined as being acute. 56% of the patients received antibiotics prior to their diagnosis however only 3% were culture negative. 89% were monomicrobial and 11% polymicrobial. The intended management strategy was a DAIR in 38% of patients and a 2-stage revision in 12% of cases. The intended management strategy was successful in 46% of the patients.The ACT is uniquely placed to analyze and create a local PJI database. This will allow us to guide further treatment and local guidelines in terms of management of these complex patients.

THE PROFILE OF CAUSAL PATHOGEN OF HIP/ KNEE PROSTHETIC JOINT INFECTION (PJI): A SINGLE CENTER STUDY

Introduction: One of the most challenging and serious complications associated with total joint arthroplasty is prosthetic joint infection (PJI). Advancements in prevention, diagnosis, and treatment of PJI seem promising. Accurate identification of the causal pathogen is a key factor for successful treatment and also for choosing antibiotic treatment. This study was aimed to evaluate the prevalence of PJI and distribution of causative pathogen using microbiological culture and pathological examination. Methods: A retrospective descriptive study was conducted by collecting data from our center registry from 2018 to 2020. The inclusion criteria of this study were patients diagnosed with hip or knee PJI based on the diagnostic criteria for PJI. The exclusion criteria were incomplete microbiology data which were either refusal to participate or loss of contact. The data extracted from medical records are demographic data such as age, sex, and microbiology and pathological examination data. Results: A total of 1359 total hip/ knee arthroplasty surgeries were performed during the years 2018–2020. Among them, 1031 were total knee arthroplasty (TKA) and 321 were total hip arthroplasties (THA). During the same period, a total of 52 patients with PJI were treated at our center. There were 31 knee PJI cases (59.61%) and 21 were hip PJI cases (40.38%). Microbiology culture and pathologic anatomy results showed gram positive Staphylococcus sp bacteria, which was the common causal pathogen of PJI. Negative culture results were found in 10/52 (19.23%) of cases. Conclusions: Staphylococcus sp was the most common causal pathogen of Hip/ Knee PJI in our center. Relatively high rate of culture-negative PJI was observed in this study, further strategies are needed to increase the rate of causal pathogen isolation in hip/ knee PJI cases in our center.

Prosthetic Joint Infection in Mega-Arthroplasty Following Shoulder, Hip and Knee Malignancy-A Prospective Follow-Up Study.

The risk of prosthetic joint infection (PJI) in mega-prosthesis for malignancy is increased compared with non-tumor cases. While several studies describe PJI in tumor-related arthroplasty, prospective studies comparing infection characteristics among different joints are limited. The present study analyzes mega-arthroplasty for hip, knee, and shoulder malignancy and compares the epidemiology, diagnosis, microbe spectrum, treatments, and outcomes between the different entities. The retrospective inclusion criteria were as follows: (1) mega-arthroplasty (2) in the hip, knee, or shoulder joint and a total femur arthroplasty (3) following a malignant bone tumor or metastasis (4) between 1996 and 2019. All included patients were prospectively followed and invited for a renewed hospital examination, and their PJI characteristics (if identified) were analyzed using both retrospective as well as newly gained prospective data. A PJI was defined according to the Infectious Disease Society of America (IDSA) and re-infection was defined according to the modified Delphi Consensus criteria. In total, 83 cases of tumor mega-arthroplasty at a mean follow-up of 3.9 years could be included (32 knee, 30 hip, and 19 shoulder cases and 2 cases of total femur arthroplasty). In total, 14 PJIs were identified, with chondrosarcoma in 6 and osteosarcoma in 3 being the leading tumor entities. Knee arthroplasty demonstrated a significantly higher rate of PJI (p = 0.027) compared with hips (28.1% vs. 6.7%), while no significant difference could be found between the knee and shoulder (10.5%) (p = 0.134) or among shoulder and hip cases (p = 0.631). The average time of PJI following primary implantation was 141.4 months in knee patients, 64.6 in hip patients, and 8.2 months in shoulder patients. Age at the time of the primary PJI, as well as the time of the first PJI, did not show significant differences among the groups. Thirteen of the fourteen patients with PJI had a primary bone tumor. Statistical analysis showed a significant difference in the disadvantage of primary bone tumors (p = 0.11). While the overall cancer-related mortality in the knee PJI group (10%) was low, it was 50% in the hip and 100% in the shoulder group. The risk of PJI in knee tumor arthroplasty is significantly increased compared with hips, while cancer-related mortality is significantly higher in hip PJI cases. At the same time, mega-prostheses appear to be associated with a higher risk of infection due to a primary bone tumor compared with metastases. The study confirms existing knowledge concerning PJI in tumor arthroplasty, while, being one of the few studies to compare three different joints concerning PJI characteristics.

Nanopore 16S amplicon sequencing enables rapid detection of pathogen in knee periprosthetic joint infection

ObjectivesWe investigated whether nanopore 16S amplicon sequencing is capable of bacterial identification in patients with knee prosthetic joint infection (PJI), and we compared its efficacy with conventional culture studies. MethodsIn total, 36 patients who had clinical manifestation suspected of PJI were enrolled in this study. To begin, synovial fluids were aspirated from the affected knee using aseptic technique and tissues specimens were obtained during the surgery. Next, DNA was extracted from the synovial fluid or tissues, and 16S rDNA PCR was performed. In PCR positive cases, nanopore amplicon sequencing was then performed for up to 3 h. The results of amplicon sequencing were compared to those of conventional culture studies. ResultsOf the 36 patients enrolled, 22 were classified as true infections according to the MSIS criteria whereas 14 were considered uninfected. Among the 22 PJI cases, 19 cases were culture positive (CP-PJI) while three cases were culture negative (CN-PJI). In 14 of 19 (73.7 %) CP- PJI cases, 16S sequencing identified concordant bacteria with conventional culture studies with a significantly shorter turnaround time. In some cases, nanopore 16S sequencing was superior to culture studies in the species-level identification of pathogen and detection of polymicrobial infections. Altogether, in the majority of PJI candidate patients (32 of 36, 88.9 %), 16S sequencing achieved identical results to cultures studies with a significantly reduced turnaround time (100.9 ± 32.5 h vs. 10.8 ± 7.7 h, p < 0.001). ConclusionsNanopore 16S sequencing was found to be particularly useful for pathogen identification in knee PJI. Although the sensitivity was not superior to culture studies, the nanopore 16S sequencing was much faster, and species-level identification and detection of polymicrobial infections were superior to culture studies.

Prosthetic Joint Infection Due to Cardiobacterium hominis: Report of First Known Case and Review of C. hominis Septic Arthritis Literature

Introduction. The Cardiobacterium species is a pleomorphic Gram-negative bacterium discovered in 1964 and is part of the HACEK (Haemophilus, Aggregatibacter, Cardiobacterium, Eikenella, and Kingella) group of organisms known to cause endocarditis. It has low virulence and can also cause dacryocystitis, septicemia and abdominal abscess. We report a patient with C. hominis prosthetic joint infection in the absence of definitive endocarditis. Case Report. A 57-year-old man presented to his orthopedic surgeon 17 months after left total knee arthroplasty with a 4–5-day history of left knee pain following yard work. He had an aortic valve replacement in 2003, mitral valve repair in 2006 and bovine aortic valve replacement in 2019 (12 months previously). Aspirate of knee joint fluid was grossly cloudy. Two of two preoperative blood cultures revealed Cardiobacterium species after 4 days’ incubation. He was initially treated with intravenous vancomycin plus piperacillin/tazobactam followed by 6 weeks of parenteral ceftriaxone followed by five months of oral cefdinir. Patient is infection-free 6 months after completion of antimicrobial therapy. Discussion. Cardiobacterium hominis is a slow-growing, fastidious, capnophilic, Gram-negative bacillus commonly found in normal oral and upper respiratory flora. Google Scholar™ and PubMed®searches were conducted and this is the first reported case of prosthetic joint infection due to Cardiobacterium hominis. We found three previously reported cases of C. hominis pyogenic arthritis: one patient with native knee pyogenic arthritis, one patient with cervical spondylodiscitis and one patient with lumbar spondylodiscitis and epidural abscess. Two of these three patients had TEE-documented infective endocarditis and one had a bioprosthetic aortic valve without evident vegetation on TEE. Our patient had a bioprosthetic aortic valve without TEE evidence of endocarditis. C. hominis should be added to the list of organisms that can cause bacteremically spread prosthetic joint infection.

P152 African Woman With a Knee Knocked by a Rare Dematiaceous Fungi

Poster session 2, September 22, 2022, 12:30 PM - 1:30 PMObjectives/IntroductionIncidence of fungal peri-prosthetic joint infection (PJI) is rare (1%-3%) and the majority are caused by Candida and Aspergillus. We report a peri-prosthetic knee joint infection caused by a rare dematiaceous fungi—pleurostomophora richardsiae, probably the first case in the world.Methods/Case DetailsA 78-year-old East African female from Malawi, housewife, with no known medical comorbidities presented with a chronic history of left knee pain and pus discharge. She had left knee pain since 2008 and was given several intra-articular injections between 2008 and 2010 for pain relief suspecting osteoarthritis. She denied a history of splinter injuries, trauma, systemic, or constitutional symptoms.In 2010 she underwent left total knee replacement (TKR) in the USA, but the pain persisted post-operatively associated with intermittent swelling of both knees. She was evaluated again in 2015 and revision left TKR done with single stage exchange.She was asymptomatic for a few years but symptoms worsened again and drainage of pus from her left knee started in December 2019. She was treated in Malawi with multiple courses of parenteral and oral antibiotics but did not improve.She presented to our hospital in January 2022 with swelling in left knee and restriction of movements. On examination, a discharging sinus was noted over the medial aspect of left knee. She was anemic with a normal leucocyte count, HIV negative, ESR of 85 mm/h, and CRP of 23 mg/L. Her renal and liver function tests were normal. CT left leg with sinogram showed features of chronic osteomyelitis of left distal femur and proximal tibia with active sinus tract in left tibia.Sinus tract excision with removal of prosthesis, debridement, and antibiotic cement spacer insertion was done. Bone and peri-prosthetic tissue were sent for histopathology and microbiological analysis including fungal and mycobacterial cultures. Xpert MTb was negative.Histopathology showed granulomatous synovitis with fungal hyphae and spores. Cultures grew a slender septate dark pigmented fungus, Pleurostomophora richardsiae which was confirmed by fungal PCR sequencing of internal transcribed spacer (ITS) region.Results/TreatmentShe was treated with Liposomal amphotericin B 5 mg/kg IV OD for 2 weeks followed by oral Itraconazole. She had persistent raised inflammatory markers at 4 weeks which settled after changing to posaconazole for 2 weeks. Conservative management will continue for 3-6 months with second stage revision arthroplasty/arthrodesis later.ConclusionDematiaceous fungi usually cause skin and soft tissue infections and they are extremely rare in causing prosthetic joint infection. Case reports of P. richardsiae causing osteomyelitis of foot and endocarditis are available but we couldn't find a published case of prosthetic joint infection caused by it. Identifying the causative organism in PJI is the most important step because the management depends mainly on it.Two-stage exchange in combination with antifungal administration between stages and post-revision should be the procedure of choice for fungal PJI. Incorporation of antifungal agents into cement spacers appears to be effective in eradicating local infections and reducing the duration of antifungal treatment and should be strongly considered.

Transfusion Rates in the Operative Treatment of Prosthetic Hip and Knee Infection.

Surgery for prosthetic joint infection (PJI) can often lead to significant blood loss, necessitating allogeneic blood transfusion (ABT). The use of ABT is associated with higher rates of morbidity and death in revision total joint arthroplasty, particularly in the treatment of PJI. We compared ABT rates by procedure type among patients treated for PJI. We retrospectively reviewed 143 operative cases of hip and knee PJI performed at our institution between 2016 and 2018. Procedures were categorized as irrigation and debridement (I&D) with modular component exchange (modular component exchange), explantation with I&D and placement of an antibiotic spacer (explantation), I&D with antibiotic spacer exchange (spacer exchange), or antibiotic spacer removal and prosthetic reimplantation (reimplantation). Rates of ABT and the number of units transfused were assessed. Factors associated with ABT were assessed with a multilevel mixed-effects regression model. Of the cases, 77 (54%) required ABT. The highest rates of ABT occurred during explantation (74%) and spacer exchange (72%), followed by reimplantation (36%) and modular component exchange (33%). A lower preoperative hemoglobin level was associated with higher odds of ABT. Explantation, reimplantation, and spacer exchange were associated with greater odds of ABT. Antibiotic spacer exchange and explantation were associated with greater odds of multiple-unit transfusion. Rates of ABT remain high in the surgical treatment of PJI. Antibiotic spacer exchange and explantation procedures had high rates of multiple-unit transfusions, and additional units of blood should be made available. Preoperative anemia should be treated when possible, and further refinement of blood management protocols for prosthetic joint infection is necessary. [Orthopedics. 2022;45(6):353-359.].